Making a 2-stroke extra quiet
Posted 07 September 2010 - 10:38 PM
Posted 07 September 2010 - 11:05 PM
Posted 08 September 2010 - 12:18 AM
You win. That is the quietest setup I have ever seen. I can't imagine it being any quieter than what you have . You can probably go underwater a littlelonger at river crossings too with the snorkel. How is the smell of the rubber after you have been running the bike for awhile? Isn't it kind of strong?
Posted 08 September 2010 - 02:05 AM
Can point me to an internet source for silicone sheet and tape?
Edit: My 2010 300XC-W has a pretty quiet stock exhaust that I've added a DbSnorkel to. With some expansion chamber muffling it's gonna be sweet.
Posted 08 September 2010 - 02:22 AM
Posted 08 September 2010 - 09:49 AM
I'm in the middle of a similar expansion pipe wrap. I'm going to try using fiberglass muffler packing (the kind of 4 storkes that's woven into sort of a blanket) for temperature tolerance and sound absorbtion. Then I may do an outside layer of fiberglass cloth / resin to make a waterproof outer shell.
Posted 08 September 2010 - 09:56 AM
please update us.
maybe a soundclip or youtube video of it running?
Posted 08 September 2010 - 10:06 AM
Posted 09 September 2010 - 05:22 PM
A crf150 is louder than a 250 2 stroke....
Posted 09 September 2010 - 10:52 PM
The silicone is vulnerable to tearing and the rubber is much tougher. The silicone has held up for years on my trials bike and it looks like the rubber innertube will last even longer. A car heater hose is covering the small diameter of the which doesn't seem the make that much difference. If you bang on a stock expansion pipe, it is like a giant cowbell, so that is where much of the noise is coming from. I now also have an exhaust guard wrapped under the rubber. The finishing tape I use is called Xtreme Tape Silicone Stretch Wrap 1" X 10' Black which is available at Amazon, Fry's electronics store and your local hardware store under different brand names.
Posted 12 September 2010 - 05:26 AM
i have been trying to call db snorkel from canada.....800 number does not work....do you have a local number for them? I have a 1979 husky that does not pass noise tests....
Posted 12 September 2010 - 09:14 AM
Posted 13 September 2010 - 08:51 AM
Posted 13 September 2010 - 11:31 AM
Posted 25 October 2010 - 11:05 AM
Posted 25 October 2010 - 05:51 PM
that expansion pipe rings like a bell; I was planning on putting a header wrap on it to keep the contact temp down, then using some "tek-lite" car audio noise reduction material on top of the wrap.
the only things I'd add are:
-the airbox also makes a good amount of noise. don't believe me? take off the seat, and gently stroke the throttle...louder, eh? for that reason, "seal off" the rear corners of the airbox, so sound can't slip through the corners,
-to further dampen that intake roar, lay some sound damping materials on the inside of the side panels and under the seat
Posted 26 October 2010 - 08:02 AM